Exhaust muffler



July 17, 1934. F. F. HAMILTON EXHAUST MUFFLER Filed July 30, 1932 INVEHTOR Francis F. H

Attorn ea 6- Patented July 17, 1934 UNITED STATES PATENT OFFICE EXHAUST MUFFLER 6 Claim.

This invention relates to the art of muillers particularly of the type adapted for use in silencing the exhaust of gas engines of the internal combustion type.

A primary object of the invention is to provide a simple structure easily manufactured and assembled at a relatively low cost of production which will not only silence the exhaust at high speed but also at low speeds and upon deacceleration. A further primary object of the invention is not only to silence the exhaust gases at all speeds and under all conditions but also to achieve such a result' at a relatively low back pressure upon the pipe discharging into the mufiler. A still further important object of the invention is to provide a structure which will operate at a relatively low back pressure on the engine discharge pipe and at the same time create a pressure in the muffler discharge or tail pipe.

become apparent to those skilled in the art in the following description of the invention as illustrated in the accompanying drawing, in which Fig. 1 is a fragmentary side elevation of a muffler embodying my invention;

Fig. 2, a vertical transverse section on the line 2-2 in Fig. 1;

Fig. 3, a vertical transverse section on the line 3-3 in Fig. 1; and

Fig. 4, a vertical transverse section on the line 4--4 in Fig. 1.

Like characters of reference indicate like parts in the several views in the drawing.

I form a cylindrical shell 10 and fix the forward closure head 11 and rear closure head 12 in each end thereof. These heads are essentially dish-shaped plates with the concave faces turned inwardly. An intake pipe 13 is carried centrally through the head 11 and fixed thereto to extend to within the shell 10 a short distance. On the end of the pipe 13 which projects to within the shell 10 is mounted an exhaust head 14. This head 14 is built up by welding together the rims of the two cups l5 and 16, the cup 15 receiving the pipe 13 centrally therethrough and the cup 16 having a convex surface 17 directed toward the open end of the pipe 13. The pipe 13 extends to within the cup 15 a substantial distance but terminates therein so as to leave a space between the end of the pipe and the convex surface 17. Both of the cups l5 and 16 are provided with a series of holes 18 and 19 respectively, cut through their walls, here shown as five in number in each cup and being formed as radial slots. The holes in each cup are aligned with the holes in the other cup.

A diaphragm 20 is fixed transversely across the shell 10 and has a shape identical with either of the heads 11 or 12 and has its dish-shape surface directed toward the head 11. A nipple 21 is fixed centrally in the diaphragm 20 to provide a passage therethrough and this nipple extends forwardly a sufficient distance to carry an outlet head 22 thereon. This head 22 resembles 85 the head 14 in that it is built up by placing the rim of the two cups 23 and 24 together and welding them therearound to form a hollow chamber discharging into the nipple 21. Both of these cups 23 and 24 are provided with a number of holes 30 through their walls, here shown as four 1n number, the holes being arranged opposite one another in the cups and being spaced around from the lower or under side so as to leave the cups closed substantially across their under sides. 5 Below the nipple 21, the diaphragm 20 is provided with a second discharge or chamber unloading opening into which is fitted a short length of pipe 25 leading rearwardly from the diaphragm.

A tail pipe 26 is carried through and fixed to the rear head 12 centrally thereof to extend for a short distance to within the shell 10. A second outlet head 27 similar in shape to the heads 14 and 22 is mounted on the inner end of the tail pipe 26 to discharge into the pipe. This head 27 has a number of holes 28, here shown as three in number, on each of the forward and rear walls arranged opposite to each other and confined to above the center of the head. All of the heads 14, 22 and 27 are provided with posts 29 which extend from the heads to bear compressively against the shell 10 as means for preventing vibration of the heads or parts thereof which would otherwise set up an objectionable sound in itself.

Exhaust gases are conducted through the pipe 13 to discharge to within the head 14 directly against the convex surface 17. Some of the gases of course will pass directly on out through the holes 19 while some of the gas will be reversed to pass out the forward holes 18, both streams of gas flowing to within the space about the head within the shell 10, so that the space between the head 11 and the diaphragm 20 will become filled with the gas. From this space, the gas may flow into the head 22 through the holes on both sides thereof and escape through the nipple 21 to the other side of the diaphragm 20.

The lower discharge opening through the diaphragm 20 permits the space or chamber between the head 11 and diaphragm 20 to unload so as to prevent excessive pressures therebetween and will be referred to in the claims as a chamber unloading opening.

The gases discharge to the rear of the diaphragm 20 in a chamber defined by the shell 10 and the rear head 12 and diaphragm 20, from which chamber the gases can escape by passing out through the holes 28 in the head 2'1 to discharge into and flow out through the tail pipe 26. Attention is directed to the structure of the various heads in that the holes therein are reduced in number in each succeeding head starting at the front end and proceeding to the rear end of the muffler. Also it is to be noted that there is practically a continuous passage through the muifier without complete reversal of all of the gases.

While I have here shown and described my invention in the form as now best known to me, it is obvious that structural changes such for example as varying the sizes and shapes of the holes in the various heads, may be made without departing from the spirit of the invention, and I therefore do not desire to be limited to that precise form beyond the limitations as may be imposed by the following claims.

I claim:

1. In an exhaust muiller, a shell, a forward closure head in the shell, an intake pipe extending through the closure head to within the shell, an exhaust head carried on the end of the pipe within the shell, said exhaust head having internal forward and rear opposing concave walls and having aligned opposing holes through both the walls, a diaphragm across the shell defining a chamber back of said closure head and having a central discharge opening therethrough, a nipple extending into the chamber from said opening, an outlet head carried on said nipple having forward and rear opposing concave walls with oppositely aligned holes through the walls, and said diaphragm having a chamber unloading opening in addition to said first opening, the exhaust head and outlet head both being in the same chamber between the casing head and the diaphragm, said exhaust head having a convex surface opposite the end of said intake pipe, and said outlet head having a less total effective area of holes than that of the exhaust head.

2. In an exhaust mufiler, a shell, a forward closure head in the shell, an intake pipe extending through the closure head to within the shell, an exhaust head carried on the end of the pipe within the shell, said exhaust head having internal forward and rear opposing concave walls and having aligned opposing holes through both the walls, a diaphragm across the shell defining a chamber back of said closure head and having a central discharge opening therethrough, a nipple extending into the chamber from said opening, an outlet head carried on said nipple having forward and rear opposing concave walls with oppositely aligned holes through the walls, and said diaphragm having a chamber unloading opening in addition to said first opening, the exhaust head and outlet head both being in the same chamber between the casing head and the diaphragm, said exhaust head having a convex surface opposite the end of said intake pipe, and said outlet head having a less total effective area of holes than that of the exhaust head, the holes in said outlet head being grouped to leave a closed area about said outlet head adjacent said unloading opening.

3. In an exhaust muilier, a shell, a forward closure head in the shell, an intake pipe extending through the closure head to within the shell, an exhaust head carried on the end of the pipe within the shell, said exhaust head having internal forward and rear opposing concave walls and having aligned opposing holes through both the walls, a diaphragm across the shell defining a chamber back of said closure head and having a central discharge opening therethrough, a nipple extending into the chamber from said opening, an outlet head carried on said nipple having forward and rear opposing concave walls with oppositely aligned holes through the walls, and said diaphragm having a chamber unloading opening in addition to said first opening, the exhaust head and outlet head both being in the same chamber between the casing head and the diaphragm, a closure head across the rear end of said shell defining a chamber back of the diaphragm, a tail pipe leading through the last closure head, and an outlet head over the inner end of said tail pipe, said last outlet head being approximately the same in shape as that of the said first outlet head, and having oppositely aligned holes through its forward and rear wall.

4. In an exhaust muilier, a shell, a forward closure head in the shell, an intake pipe extending through the closure head to within the shell, an exhaust-head carried on the end of the pipe within the shell, said exhaust head having internal forward and rear opposing concave walls and having aligned opposing holes through both the walls, a diaphragm across the shell defining a chamber back of said closure head and having a central discharge opening therethrough, a nipple extending into the chamber from said opening, an outlet head carried on said nipple having iorward and rear opposing concave walls with oppositely aligned holes through the walls, and said diaphragm having a chamber unloading opening in addition to said first opening, the exhaust head and outlet head both being in the same chamber between the casing head and the diaphragm, a 010- sure head across the rear end of said shell defining a chamber back of the diaphragm, a tail pipe heading through the last closure head, and an outlet head over the inner end of said tail pipe, said last outlet head being approximately the same in shape as that of the said first outlet head, and having oppositely aligned holes through its front and rear wall, said exhaust head having a convex surface opposite the end of said intake pipe, and said outlet head having a less total effective area of holes than that of the exhaust head, said second outlet head having a less total eflective area of holes than that of the first utlet head.

5. In an exhaust muiiier, a shell, a forward closure head in the shell, an intake pipe extending through the closure head to within the shell, an exhaust head carried on the end of the pipe within the shell, said exhaust head having internal forward and rear opposing concave walls and having aligned opposing holes through both the walls, a diaphragm across the shell defining a chamber back of said closure head and having a central discharge opening therethrough, a nipple extending into the chamber from said opening, an outlet head carried on said nipple having forward and rear opposing concave walls with oppositely aligned holes through the walls, and said diaphragm having a chamber unloading opening in addition to said first opening, the exhaust head and outlet head both being in the same chamber between the casing head and the diaphragm, a closure head across the rear end .0! said shell defining a chamber back of the diaphragm, a tail pipe leading through the last closure head, and an outlet head over the inner end of said tail pipe, said last outlet head being approximately the same in shape as that 01' the said first outlet head, and having oppositely aligned holes through its front and rear wall, and a discharging pipe leading from said diaphragm unloading opening toward a part of said second outlet head having no holes therein.

6. In a exhaust muiller, a shell, a forward closure head in the shell, an intake pipe extending through the closure head to within the shell, an exhaust head carried on the end 01' the pipe within the shell, said exhaust head having internal forward and rear opposing concave walls and having aligned opposing holes through both the walls, a diaphragm across the shell defining a chamber back of said closure head and having a central discharge opening therethrough, a nipple extending into the chamber from said opening, an outlet head carried on said nipple having forward and rear opposing concave walls with oppositely aligned holes through the walls. the exhaust head and outlet head both being in the same chamber between the casing head and the diaphragm, and said diaphragm having a chamber unloading 0pening in addition to said first opening, a closure head across the rear end of said shell defining a chamber back of the diaphragm, a tail pipe heading through the last closure head, and an outlet head over the inner end of said tail pipe, said last outlet head being approximately the same in shape as that oi the said first outlet head, and having oppositely aligned holes through its front and rear wall, and said outlet head having a less total effective area of holes than that of the exhaust head, said second outlet head having a less total effective area 01 holes than that of the first outlet head.

FRANCIS Fa HAMILTON. 

